Question

Milk secretion is caused by:-
(a)Progesterone
(b)PRH
(c)PRL
(d)Oxytocin

Answer 1

Hint: The hormone that is responsible for milk secretion from mammary glands is produced by the hypothalamus and is stored in the posterior pituitary. This hormone causes milk secretion by inducing contraction of the muscles in mammary glands.

Complete answer:
The hormone responsible for milk secretion is oxytocin. It is thus known as the milk ejection hormone. It stimulates the mammary glands to eject out milk that is stored in them. Mammary glands are modified sweat glands that are present over the pectoral muscles. These glands have cells called alveoli that produce milk. Milk production is done by the hormone prolactin that is secreted by the anterior pituitary. Oxytocin also helps during childbirth by contracting the muscles of the cervix and uterus.

Additional Information: Let us know more about the pituitary gland.
-The pituitary gland is known as the master gland as it controls all the other endocrine glands present in the body.
-But the pituitary itself is controlled by the hormones of the hypothalamus, thus the hypothalamus is known as the master of the master gland.
-The pituitary gland is made up of the anterior pituitary and posterior pituitary anatomically.
-The anterior pituitary releases many hormones such as growth hormone, prolactin, the thyroid-stimulating hormone which control the organs of the body.
-The posterior pituitary releases oxytocin and vasopressin which were produced in the hypothalamus and were transferred to the pituitary axonally.
-Vasopressin is responsible for water absorption from urine and thus prevents the formation of urine.
-Urine formation is known as diuresis and because vasopressin prevents this, it is known as an anti-diuretic hormone.
So, the correct option is ‘Oxytocin’.

Note: -When there is underproduction of the vasopressin hormone, it leads to a disease known as diabetes insipidus.
-Each mammary gland consists of 15-20 glandular lobes that are separated with the help of dense connective tissue and adipose tissue.
-The milk is ejected out through the lactiferous duct which opens out the nipple.